1. Field of the Invention
This invention relates to an adjustable flow rate fluid atomization nozzle.
More particularly the invention relates to a nozzle which comprises an elongated tubular body of the corona cavity type, such as described in U.S. Pat. Nos. 3,584,786, 3,737,101 and 3,737,517, issued to William H. Johnson and assigned to Patent and Development of North Carolina, Inc., having a discharge end terminating in a single plane surface, a structured device having a single plane surface which is attached with its plane surface contiguous with the plane surface of the tubular-like body, and a slit-like aperture formed between the single plane surfaces of the tubular body and the structured device. The slitted aperture comprises a depression formed in the structured device to provide a flow path between the contiguous surfaces which is directed laterally outwardly from the axis of the tubular body. The head of the end machine screw can be used in one embodiment as a structured device. In another embodiment the depression is formed in both the contiguous plane surface of the tubular body and the structured device. The flow rate of the nozzle is adjustable by changing the size of the slitted aperture in one of several ways subsequently to be described.
2. Description of the Prior Art
Patents representative of the prior art of which applicant is aware are:
U.S. Pat. No. 1,121,654 Myers, Dec. 22, 1914
U.S. Pat. No. 3,584,786 Johnson, June 15, 1971
U.S. Pat. No. 3,737,101 Johnson, June 5, 1973
U.S. Pat. No. 3,731,517 Johnson, May 8, 1973
U.S. Pat. No. 3,584,792 Johnson, June 15, 1971
U.S. Pat. No. 3,252,661 Aldrich, May 24, 1966
U.S. Pat. No. 3,109,593 Newland, Sr., Nov. 5, 1963
U.S. Pat. No. 683,646 Gibbs, Oct. 1, 1901
U.S. Pat. No. 977,748 Milburn, Dec. 6, 1910
The Johnson U.S. Pat. Nos. 3,584,786, 3,584,792, 3,731,517, and 3,737,101 disclose fluid dispersion nozzles which have a main feed cavity and at least one fluidly connected corona orifice cavity. The term corona is used in describing the corona orifice cavity because the corona orifice cavity is crown-like and protrudes outwardly from the main feed cavity. The fluid atomization nozzles of the Johnson patents comprise a relatively large elongated main fluid feed conduit or body containing the main feed cavity and at least one smaller elongated discharge corona orifice portion or wing extending outwardly from the main feed conduit and forming the corona orifice cavity in section. The corona orifice cavity has spaced side wall surfaces extending outwardly from the main feed cavity and an arcuate end surface connecting the spaced side wall surfaces remote from the main feed cavity. The arcuate end wall surface of the corona orifice portion is slit transversely at one or more locations to form one or more orifices for fan shaped fluid dispersion. The arc diameter of the arcuate end wall surface ranges down to as little as 0.001 inch depending upon the degree of atomization desired and the included angle of the arcuate end wall may range up to 180.degree..
The Johnson nozzle disclosed in the aforesaid Johnson Patents achieve a finer degree of atomization and a wider angle of flat-fan atomization than had previously been achievable with other single unit nozzles. The uniqueness of the Johnson nozzle resides in its corona orifice cavity as a part of a long tube-like structure. The corona orifice cavity can be fabricated so that the distance between the opposing inner side walls and the diameter of the arc at its outer end wall, into which the orifice(s) is cut, may be very minute, down to 0.001 inch. The method of fabrication to achieve this character of the corona cavity is disclosed in Johnson U.S. Pat. No. 3,731,517. This produces a very fine fog-like atomization and a very wide angle fan-shaped dispersion. However, once the orifice is cut there is no way to adjust its opening dimensions except to enlarge them and thus only to increase the discharge rate. The discharge rate cannot be reduced in any other known practical manner, keeping all other factors constant. These latter factors are: (1) control of the quantity of fluid allowed to enter the main feed cavity and thence to the corona cavity and out through the slitted orifice; and (2) control of the fluid pressure at the orifice by changing the diameter of rotation and/or the speed of rotation (R.P.M.) in the case of rotary nozzle disclosed in U.S. Pat. No. 3,737,101, and by changing the pressure regulator in the fluid supply line in the case of stationary nozzles disclosed in U.S. Pat. Nos. 3,584,786 and 3,731,517. The aforementioned factors 1 and 2 do decrease the degree of atomization if any one or both are used.
3. Description of the Invention
This invention permits any individual, manufacturer or user to quickly and easily adjust the flow rate. Its main advantage lies with the manufacturer. He can provide the flow rate of discharge to meet the customer's discharge specifications by simply changing and/or positioning structured device(s). All elements can be mass produced to one set of specifications for each. This process materially decreases the cost of production.
As previously described this invention applies only to an aperture in the extreme outer end of the corona orifice structure. It does not apply to those apertures that may be cut along its length as described in Johnson U.S. Pat. No. 3,584,786.
In this invention the outer end of the corona orifice structure is machine cut and formed at right angle to the lengthwise axis of the structure. The center feed cavity is threaded at its outer end to receive a machine screw containing a structured device whose outer diameter is comparable to the outer dimensions as measured across the opposing corona orifice cavities, and will therefore just cover the end of one or more corona cavity(ies).
Securing a slitted aperture by partially closing the plane end of the corona cavity body with a structured device in which depressions of varying capacities are formed effects desired calibrations. The structure of this device could be applied to the end machine screw.
In some structured devices, depending on the shape, the end slitted aperture becomes a combination of half corona orifice with its before expressed wide angle flat fan, fine degree of atomization and a fanning out dispersion achieved by impinging fluid against a surface. This combination results in a small loss in the wide included angle of the fan and the degree of atomization, but is offset by the superior values achieved in manufacture and sales service. In one embodiment of the structured device covered herein, the shape of the aperture forms half of a true slitted aperture and meets precisely the specifications as revealed in Johnson U.S. Pat. No. 3,584,786. When combined and symmetrically positioned with the end of a corona orifice cavity in which half of the corona type aperture is formed, a true slitted corona aperture as described by Johnson results. A uniform flow of fluid to the aperture from both sides is achieved.
Two basic structured devices may be used and are described as follows:
1. The structured device has one or more depressions on the plane side to mount next to the plane end of the corona orifice structure. The depression can take any shape. For example, it may be a plane surface sloping from the outer edge inwardly. If the inner surface of the head of the end closure screw is used, a cone-shaped surface must extend completely around the circumference. The size of the aperture opening is adjustable in this case by changing to a screw having a different cone-shaped surface. The aperture can be formed with one-half in the structured device and the other half in the corona cavity. The adjustment of the rate will be described later herein. The difference between the two apertures lie in the fan type dispersion. When cut in the structured device only, the flat surface of the atomized fan is directed outwardly at an acute angle, slightly less than 90.degree. to the central axis of the corona structure. When cut, half in the structured device and half in the corona cavity, the flat of the fan is essentially 90.degree. to the lengthwise axis of the corona structure. Either of the above does not detract significantly from the degree of the atomization. The less than 90.degree. angle improves somewhat the atomization in the rotatable unit.
Another example is a depression formed on the cooperating surface of the structured device shaped exactly and positioned symmetrically to a corona orifice cavity with one-half of a slitted aperture of the Johnson type. When both parts are so constructed and positioned, the result is an excellent corona type slitted aperture with near comparable results.
2. The structured device has one or more protrusions on its plane surface. The protrusion is shaped generally to the arc formed in the end of the corona cavity, as machined at an acute angle to the center axis on the outer end of the corona cavity. All surfaces, except the aperture opening, on the corona cavity body and the structured device fit tightly. The purpose of the protrusion is to cut down on the width of the aperture opening, not the angle of the arcuate end, when positioned to fit symmetrically within the orifice as cut in the corona cavity. The head of the end closure screw cannot be used in this case.
The rate of fluid discharge for No. 1 above is altered in one of two basic ways: one, positioning one of the depression shapes formed in one structured device plane face with the corona orifice cavity; two, positioning a structured device having the desired depression. In both cases the structured device may be retained in position by the end machine screw, also with the help of a suitably formed stop if so desired. The latter is commonly used in industry.
The rate of fluid discharge for No. 2 is altered by simply changing the structured device--one with a small protrusion for maximum rate; one with a large protrusion for reduced rate. These structured devices are also retained in place by the same end machine screw.
All structured devices may be identified by fluid rate calibration marks appropriately placed.
The maximum aperture opening should be formed so that the rate does not exceed the maximum safe power output in the case of the rotary motor operated unit.
In summary this invention comprises a corona type body and a structured device of comparable outside diameter. The outer end of the corona structure and the inner surface of the structured device when properly formed, fitted and fastened together forms a slitted aperture to produce flat fan shaped atomization patterns. The structured device is adjustable by changing to a different size of depression or protrusion having a different fluid discharge rate. The dimensions of the aperture are changed in this manner.